Hello, I was wondering if anyone could point me to a list or give me some suggestions of some good literature of Tibetan Buddhism from prior to the 20th century, preferably medieval works. I asked a similar question before regarding literature on Dzogchen actually, but now I am looking more broadly in scope. To give a good example of what I am talking about, it could be actual scriptural sources, commentaries on scripture, or works by Tibetan masters, such as Longchenpa or Dolpopa for example. Anything you can suggest (in English of course) would be greatly appreciated as I need to expand my knowledge on Tibetan Buddhism and am looking for some new reading material. While I have nothing against modern literature or masters, I can always find sources on such material, whereas hearing recommendations about older literature isn't as easy to come by.